This invention relates to an analog integrated circuit delay line using micropower techniques, and more particularly to an electronically variable analog delay line implemented with very large scale integrated circuit (VLSI) technology.
Integrated circuits using micropower (0.5 .mu.W at 1.5 V) techniques have been used first for digital watches and pocket calculators, some having so many functions as to require sophisticated architectures very much like large processors. The use of micropower techniques has since been extended to integrated circuits that more directly affect the health and well being of man, such as pacemakers and hearing aids. But in both of those applications, the integrated circuits are designed to merely assist the sophisticated systems of man, and not to supplant them.
A "stone deaf" person who has lost all functions of the cochlea cannot be helped by a hearing aid. He requires, instead, a complete and independent hearing system. Similarly, the vision of a blind person cannot be aided by electronic devices, but must instead be supplanted with a complete and independent system. In order that such systems be developed, auditory and visual signal processing by the cochlea and the retina must first be analyzed and synthesized for research. It may be possible to synthesize a system that supplants the inoperable system of man for the deaf or the blind.
Notwithstanding such a laudable goal for helping man, the electronically variable active analog delay line that is the subject of this invention will have other, and possibly more readily applicable uses. Consequently, the objects of this invention should be construed broadly, notwithstanding reference to its application to electronically emulating the operation of the cochlea.